Acclimation
by Batty Musings
Summary: Sooner or later each and every one of the guardians would have to face fact—Jack Frost was growing up.
1. Chapter 1

**A/N:** This has been in my fic folder for like forever (like I'm talking since a week after the movie came out) and I was just like eh screw this and decided to put it up. There are three other parts after this, detailing a meeting with each other guardian, the last being Tooth herself. So. Yep. I already have it all done, so no pressure there. I'll also try to regularly update, pending motivation to edit each part.

* * *

**Acclimation**

**Part I**

* * *

It started off slowly, so slowly that none of them were even able to believe it at first.

Sure, there were a couple more arguments cropping out between him and Bunnymund-but to be honest, it simply wasn't a guardian meeting without the two of them threatening to cut each other down to size. Just cause they were both charged with protecting the children of the world didn't mean that they actually had to get _along_.

Still, someone should have realized that was a little more of the frost guardian to cut down.

To this day, North would bellow and claim that he was the _first_ to notice and it was with a certain touch of exasperation that the rest no choice to agree with the Santa's statement. Even if it meant having to put up with the smug bastard. Like he didn't already have the whole _Christmas_ thing to boost his ego. See, Old St. Nicholas had seen it come a little ways after the boy had been instated as a guardian, give or take a decade. Or two. Eh, immortality wore on your time-telling skills a little.

Jack had been prowling around the outskirts of the workshop again, gathering up the courage to launch another full frontal assault to get inside. (Even though he already had _full_ permission to use the front door. It seemed that some things were simply a matter of pride.) True to form, he had gotten rather close before the yetis had found him. Again.

North found himself disturbed in the middle of a particularly delicate operation involving a model airplane and several belligerent elves, the solid wooden door to his private office banged open. As he cursed and fumbled around trying to collect the pieces of his failed experiment, a certain white mess was quickly deposited onto his carpet.

"_Jack_."

A smirk. "Santa."

Pinching the bridge of his nose, North sent away his yetis with a wave of his hand, trying very hard not to notice the way Jack looped his cane around the leg of a yeti named Phil and nearly sent him sprawling.

"Dwbard urghwetee!" Phil retorted as he shot a nasty glare, or the closest thing to it in yeti form, at the snickering kid as he left. North hoped the two didn't hurt each other too badly later. Yeti labor didn't come cheap. Well, it did, but there was no need to make them question their loyalties.

Sighing loudly, North repeated, "Jack?"

The frost guardian in question looked back at him with wide eyes, seemingly the paradigm of innocence. It didn't fool the bulky Santa for a moment.

"Don't you have somewhere else to be, some _children_ to make happy?" North not-so-subtly hinted at younger boy.

Jack shrugged and replied, "Nah, not really. I mean, you guys are all cool and stuff with your '_deadlines',_" He rolled his eyes and held his fingers up to put quotes around the seemingly outlandish word, "but man, I just gotta have fun and make sure kids have some fun too."

North's face twitched ominously. "And you still chose to invade _my_ workshop _two_ _days_ before Christmas, _why_?"

A familiar grin that described exactly how Jack had become current record-holder of the naughty list crept onto his face. "Cause it's fun, _duh_."

There was a moment of silence as the bearded guardian tried to rationalize away the sudden urge to sic his elves on Frost. North pointed to the door. "Out."

No matter how satisfying it would be to watch the boy struggle in a pile of red and putrid elves, he would probably just find a way to reverse it on him. And after the last incident he would rather not chance such a thing, especially since the elves were _still_ mumbling about their failed attempt to unionize.

Jack rose to his feet easily and with a quick burst of artic wind, his signature grin never leaving his face for a moment. North watched him carefully, the cogs turning in his head as he finally registered the lack of a certain someone. As Jack started to leave, his cane dragging on the floor and creating a trail of ice that would take hours to melt off completely, North added nonchalantly, "Besides, you should best be preparing for the next guardian meeting. In a week."

Jack stilled for a moment, tensing up as he said suspiciously, "There's no guardian meeting for the next couple months. Bunnymund told me."

So the boy had already been to see the Easter Bunny. North shook his head pityingly and lied, "It's a celebratory meeting. After Christmas. We have them every couple years. Eh, Bunnymund must have just neglected to tell you. He does that to people he wants to push off cliffs."

"Oh." There was no trace of anything other than vague interest in his statement, certainly no hint of the relieved sigh Jack let loose, or the way he relaxed at the mere mention of meeting up with the other guardians.

North knew that he should just leave it at that, but he couldn't help but adding softly, "I'm sure Babytooth is fine. Her too."

There was a pause where the room turned frigid—which was saying something as they were currently the North Pole. A quick snort signaled a return to the previous temperature, and Jack turned with a smile, his white hair falling to the side as he tilted his head and said, "I have _no_ idea what you're talking about."

North eyed him back critically, taking in the sudden happy gleam in the younger guardian's eyes with interest, knowing for a fact that it hadn't been there when the boy had come in. "Yes, I am sure you don't."

Despite his nonchalance, Jack was quick to leave, his shoulder brushing that of a yeti stationed outside the door—_Phil_—and leaving icy residue on its fur. North watched with growing amusement, noting that the boy certainly hadn't been able to do that a few months ago, certainly not without using his cane to even reach to abominable beast's shoulder.

Stroking his beard softly, old Nicholas couldn't help but chuckle.

.

.

.


	2. Chapter 2

**A/N:** Yikes, meant to post this earlier but traveling held me up. Thank the lord for reviews, they reminded me that I even _had_ this fic to update. Next part is gonna be heavier on the Jack/Tooth, promise. And longer. Damn, forgot how short this part was.

* * *

**Acclimation **

**Part II**

* * *

.

.

.

It was clear to everyone that Bunnymund was the next to notice, and that was pretty much were the conversation ended on who noticed what first.

Because when Bunnymund noticed, _everyone_ noticed.

Jack's grin went from ear to ear as he took in the fuming Easter guardian. "Now, what were you saying about being taller?"

Bunnymund snarled, "I _am_ taller."

Arching a brow, Jack mused to himself, "You still think so, huh?" His mischievous gaze flickered to the side. "Hey Sandman, what d'ya say?"

The gold man frowned at the unintended jab and held up the sand-formed measuring stick for the perusal of the group. At the six-foot-one mark there was an indentation labeled with a bunny picture, and a little above that, at around ¾ of an inch more, there was another indentation of a snowflake.

"You cheated."

Jack's eyebrows flew up in amusement. "And how did I do that?"

Bunnymund's mouth flew open and he looked about to shout an explanation from the rooftops before visibly deflating as he realized that he had none. "Damn."

"Told ya so."

North chuckled and intervened, "Now, you should know when you've been beat, Easter Bunny. In this case, eh, it was two months back."

Bunnymund bristled with irritation and launched into a rant about even if the no good upstart was, like what, _two leaf-blades taller_ than him it didn't mean _anything_, especially since he could run circles around him any _day of the week_. But that still didn't change fact.

Jack Frost was growing up.

In some ways it was to be expected, what with the sheer amount of people believing in him now. And that number was growing by the day due to a urban legend about snow days that had gone viral thanks to a certain internet savvy group of little kids. And in truth, the boy _had_ been in a sort of stasis during the years where no one had known about him.

Not every guardian's form changed. But as Bunnymund himself could well attest to—_belief_ was the backbone of every single one of their powers. Even their appearance. North was just glad that it had happened when it had, taking care to remind himself that despite the boy's previous appearance, he was already centuries old. It was about time for him to start adjusting.

That's not to say that North didn't already anticipate that the frost guardian would be almost unbearably smug for the months to come. But eh, they'd go down that road eventually.

As for Bunnymund, he took a break from his accusations of bribing the man on the moon to notice that the object of his attentions wasn't paying him much attention at all, seemingly intent on gathering the response of another particular guardian. Jack stole glances from the corner of his eyes at the giggling Toothiana, who was watching Sandman mime the contest with exaggerated sand puppets. Jack puffed up his chest involuntarily and straightened when her gaze fell on him, sending her a quick grin that she didn't seem to notice as her tooth fairies crowded around her.

As she relayed information to them about a bask-ice ball game in Minnesota that had reaped buckets of teeth, Bunnymund watched the frost guardian visibly deflate as Tooth turned away. An almost uncharacteristic look of disappointment flickered across Jack's face before it was quickly replaced with the all too familiar smirk, which was lacking just a hint of _something_ to make it actually all that familiar.

Bunnymund exchanged glances with North, who had been watching the exchange as well, and soaked in the meaning of the elder guardian's slow nod.

A shit-eating grin plastered itself onto the face of the Australian rabbit.

_So this is about a sheila, yeh?_

.

.

.


	3. Chapter 3

**A/N:** Aha, finally managed to update this when I meant to! For what it's worth. Whoops.

.

.

.

**Summary**: Sooner or later each and every one of the guardians would have to face fact—Jack Frost was growing up.

* * *

**Acclimation**

**Part III**

* * *

Icy wind brushed across his cheek, chilling to anyone else, but to the guardian of frost himself it served only as a tender brush of comfort from his oldest friend. The hard grooves of a wooden rooftop endeared themselves to the other side of his face, and with a groan, Jack felt his eyes start to flicker open.

He found himself in his usual hideaway atop the largest house in town, and his yawning was a good indicator of what had just transpired. If not that, then the presence of a certain gold dream-caster standing near the corner of the roof served as a pretty good reminder.

Stretching languidly, his joints popping into place, Jack sighed and asked, "So…how long was I out?"

Sandman didn't answer, not even with a sand creation, choosing instead to stare back at the frost guardian with a thoughtful look on his shining face. Jack frowned, wondering what was going on. Sure, he would divert a couple of the Sandman's dream strands whenever he wanted to actually get a good night's sleep, knowing that the other knew and replaced them in accordance with their unofficial agreement. But he had never actually found himself face to face with the oldest guardian before.

Jack froze suddenly, a myriad of horrible thoughts running through his head. "What's wrong? Is it the guardians? Do they need me to be there? Is anyone hurt—?"

Sandman rapidly shook his head and Jack calmed instantly. So it wasn't that. Still, he fixed a quizzical look on Sandman, waiting for an answer.

After some fidgeting and a little not-so-subtle attempts to pep himself up, Sandman sighed and opened his hand, letting go of a thin strand of gold sand. Jack watched it curl towards him for a moment, looking puzzled. "A dream?"

It twisted and wrapped around him for a moment, touching his temple for a quick moment before retreating and leaving its phantom presence like a hammer in his panicking skull. "_My_ dream?"

Sandman nodded this time, a small smile creeping onto his face as the usually unflappable frost guardian began to get nervous. Swallowing nervously, Jack rubbed the back of his neck and asked as nonchalantly as he dared, "Uh, well…so, what was it, err, about?"

With a flick of his wrist, the golden guardian sent the gold sand tumbling through the air as he let loose a silent chuckle. The sliver of sand twisted and writhed through the air, seeming to expand by the second. Jack watched, his grey eyes fixated, enraptured as it formed.

First came a pair of light wings that expanded from the mound of gold. Then a delicate hand made its way out, with a coating of light feathers growing from the arm to the circular mass that curved as it formed. Jack's eyes trailed slowly upwards and his breath hitched as his dream took solid form, its glittering gaze watching him as he stepped involuntarily closer.

Her fingers reached out and brushed his cheek as a pressure seemed to settle itself over his chest, his frozen ribs tightening like a vice. His hands reached out of their own accord and settled themselves on her hips, but not before sliding down her sides slowly as he tried to understand what exactly was happening. A soft smile stretched across her face at the lackluster attempt to cage her, and her own hands reached up to chastise him with a torturously slow swipe of her thumb across his gaping lips.

An unfamiliar shiver made its way down the frost guardian's spine, and his arms moved to snake around her waist and pull her flush against him. It was hard to distinguish the dream from reality, not when his mind seemed to be moving in a haze that only got worse once he found her staring up at him, feathery eyelashes fluttering as he ducked his head in closer and—

With a light sifting sound, the dream disappeared. The figure felt away and Jack was left clutching to nothing but thin air, golden grains of sand still stuck to his fingers and silently mocking him. After taking a few deep breathing and trying in vain to calm his pounding—_dead_—heart, he finally chanced a guilty glance over at the Sandman.

Sandman watched the scene with a piteous smile, letting it go at the last moment. He tilted his head to the side as the frost guardian took him in beneath his white mass of hair and who seemed to be trying in vain to hide his face at what he perceived would be judgment. Sandman frowned. Now that wasn't his intention at all.

There was a burst of golden sand and suddenly a castle in the sky appeared, shimmering and bearing quite a resemblance to one both knew well. The minuscule fairies darting around it with sacks of teeth helped. Jack blinked for a moment before the message went through. "You want me…to go there?"

Sandman nodded again, snapping his fingers and creating another two small figures flying around the castle, one obviously Toothiana and the other the spitting image of the man before him. The replica spun in circles through the air around each other, leading each other in a complicated whirl of loops and mid-air tucks that ended with both figures clasped hand in hand as they descended, their silent breathless laughter almost phantom-like in the air around them.

Jack Frost sucked in a breath of night air that seared his dead lungs and refused to meet the eyes of the pleading Sandman.

"I can't."

The figures danced closer around him, almost taunting as the dream-maker tried to emphasize his question. _Why?_

Once again, Jack couldn't meet his eyes. A sliver of fear grew inside his chest, fed on by the thought of what failure would mean. "I _can't_."

And with that, the guardian shot himself up into the air, buoyed by the bristling wind that froze him anew and chilled his pounding heart into a slow murmur of what it once was. Seconds later, he was gone from sight, but not from mind.

The phantom sand figures fell apart at the frost god's absence, as it had been _his_ dream. Sandman fought the urge to scream at the empty night sky. A couple of hundred years and everything had been fine and dandy, but put in one more guardian and whoosh—there went the team dynamic!

Sighing deeply, Sandman wondered if it would be unethical to get the man in the moon to order the two to resolve their problems, preferably in a way that didn't end with him being privy to a rather intimate dream involving not only the man he saw as an apprentice of sorts, but also the female fairy he had thought of as a sister for centuries.

It was enough to drive the guardian of dreams mad.

.

.

.


	4. Chapter 4

**A/N**: And this is the last part! Y'all have been great, seriously. Hope you like the frostbite!

* * *

**Acclimation**

**Part IV**

* * *

**Summary**: Sooner or later each and every one of the guardians would have to face fact—Jack Frost was growing up.

.

.

.

Toothiana frowned as she watched the frost guardian float listlessly through the sky, wondering what had him so absent. "Jack?" She beat her wings fast in the cold night air, trying to make out his face through the sheen of reflective moonlight. "Are you alright?"

"Fine."

She almost flinched at his one-word answer, the coldness of it jarring from the minutes ago when he'd been grinning at her from the distance as he hurried to replace Sandman on patrol duty. His face had fallen as he caught sight of her worried gaze, mouth opening for a split second before snapping shut. Tooth furrowed her eyebrows, wondering what had happened between the two guardians so much that just the sight of the Sandman's retreating form, gold sand trailing behind, had gotten Jack so worked up.

Her frown grew into a resolute line. Flapping her wings faster Tooth zoomed forward to block his path, hands on her hips. "No, Jack. You're going to tell me! Guardians don't keep secrets!"

His blank face showed a spark of amusement as he arched a perfect brow in disbelief. She shrank back a little, amending, "Well, only a few. A couple here or there, just to keep us sane." Jack's face had definitely turned mocking now, his smirk growing by the second. She held her head high, but couldn't keep a distinctive blush from coating her cheeks at the sight of his expression. "Hey, an eternity together means that a few scattered white lies are _necessary_."

"Then count this as one of them," he replied casually, drifting ahead as his eyes lazily watched her until the last moment. Tooth told herself the shiver that raced down her spine was from the sudden cool wind.

In defiance, both to the weather and her stupid seemingly _constant_ crush, she pursed her lips together and raced forward again, aiming to stop him right in his tracks. Jack seemed to sense her movement and, with a grace that seemed to only improve with the years, levitated higher with his staff in the crook of his arm, dodging her at the last moment. Tooth fumed as she swerved to meet him, wings beating furiously as she climbed.

There was a rush of freezing wind as she gave a merry chase, fighting against the forces of nature as she spun and twirled with him, icicles coating her feathers as they rose above the clouds. Tooth tried to keep her face serious even through what seemed to amount to a godlike version of tag, but when she heard a low sound filter through the air around her, laughter that could have only come from one person, she felt her lips start to move of their own accord, stretching into a bright smile.

"Oh, I'm definitely going to catch up Jack! Why don't you save yourself the trouble and come nicely?"

Jack flashed a perfect pearly-white smile and retorted, "Well, I'm not sure if you heard, but I happen to be number _one_ on the naughty list!"

"How could I not," she teased, her cheeks starting to hurt from the combined struggle of the cold and her grin, "North grumbles about it whenever he can! You're only lucky you stopped qualifying with the growth spurt!"

He froze suddenly, stopping right in his tracks and she followed, coming to a halt a few feet away from him in confusion. Tooth tilted her head to the side and tried to catch a glimpse of his face, but the strong winds must have thrown his hood over, as it was covering his head and obscuring her curious gaze. The skies were calm now, but only like that which was in the middle of the storm—waiting.

"Is that…alright with you?"

Tooth blinked. "What is?"

A tuft of white hair peeked out from under the frostbitten hood as Jack elaborated, "The whole," he made a series of gestures with a hand before letting it drop uselessly, "Growing. Thing."

Her feathers bristled at the realization that he was asking what she thought about him and Tooth fought to keep her expression controlling, knowing that now that he was older completely losing herself as she squealed over his teeth wouldn't be welcome at _all_. Still, she let her eyes roam over his taller form, taking his sudden tenseness in absently while her gaze was a little more fixed at the filled in corners of the hoodie, or the curve of his jaw under the moonlight.

Her breath hitched as she wished she could tell the guardian exactly what she thought of him, how well he was handling what was, in some effects, a stark change in his entire being as a frost spirit, how _brave_ he always seemed to be even when she would have been completely terrified.

Despite her knowledge that he didn't think of her that way, Tooth couldn't help but sigh, "Honestly? I think you're still that same amazing Jack Frost that you're _always_ going to be."

He didn't appear to have answered, although the strong, bitterly cold winds that suddenly picked up and ran through her with all the subtlety of a handful of daggers might have swallowed up his words. Tooth strained to hear, her heart beating so fast it was like the vibration of her wings. Jack only clenched his staff and _dived_, the wisps of frost tailing his descent the only hint for her to follow.

She did so with a pressure on her chest, wondering how he'd taken her words. The fall proved to be more of a struggle than the climb, as a cold front appeared to have moved in, chilling her feathers and numbing the tips of her fingers. Her wings proved to have the hardest time, clinging together as she fought to separate the frost. He was only a little ways ahead but she still called out as loud as she could, "Jack, Jack something's wrong, I can't—"

One wing clanged together with another and refused to let go, the water vapor in the air freezing them tight. With no mode of travel, Tooth started to fall.

She struggled to keep calm even as she twisted and turned in the merciless atmosphere, her limbs rendered little more than dead weights. Her lips pried open as a cry was torn loose from the middle of her throat at the sight of the coming ground. At the last moment Tooth clenched her eyes shut, wishing she'd at least thought to bring her fairies along.

Landing with a crack, Tooth waited for the rest of the pain to manifest itself before realizing she was beginning to slip—but on what? The cool surface beneath her proved to be the answer and when she finally opened her eyes she was gliding on a thin translucent film of ice, a far ways from the ground that would have undoubtedly proved to be harder. Snow coated around the edge of the makeshift slide, smoothing her passage to the end, where she was neatly caught before she could go tumbling off.

Jack's eyes were wild as his hands clutched her tight enough that they were shaking. "I'm—I'm sorry, I didn't see you in time, I should have—"

Tooth shushed him. "No, it's fine, really, I mean, it's all my fault, I should have kept out of the chilly air."

His guilty face spoke volumes, as did the sudden clenching of his fingers, digging into the ruffles of her feathers.

"Oh," she murmured, finally realizing where the frozen winds had come from. "Well, it's still not your fault! It happens to the best of us, and I would guess especially to someone who has only just gotten the full use of his powers." Tooth straightened, pouting in defiance. "And I'm fine, so there!" She broke out into a grin, pushing her way out of his hold.

Toothiana managed to lift herself into the air for a grand total of two seconds before the happening to stretch out her ankle, causing a white-hot flash of pain to shoot through her foot. Wind started to rush by again as she fell with an agonizing cry, only to be caught quickly by a pair of shaking arms. She couldn't even look him in the face this time. "Oh." Her lashes fluttered in embarrassment as she quickly turned her head to face his blank one, repeating, "It's still not your fault!"

Jack only nodded, twice, a nerve in his jaw clenching and unclenching dangerously. Tooth resisted the urge to scream in frustration.

_Why couldn't anything go right!_

He started to gingerly lift them down onto the midair ice platform, still refusing to say a word. He took her leg in one hand and just as she was about to ask him how he intended to bandage it he held his other palm out to collect traces of white flecks in the air, frost particles that collected into a cool sheet that he then placed over the wound. He almost seemed to linger as he traced the curve of her calf, brushing aside down feathers as he continued. She shivered at the touch, either the makeshift bandage's or his.

Eons seemed to pass, which was a rather long time for an immortal creature, as Tooth waited for him to say something. After she felt about ready to rip her head-feathers out, he grunted, "Better?"

Eager to outdo herself, Tooth grinned. "Oh, much, really! Thank you, Jack. I don't know _what_ I would have done."

His guilty gaze, if only for a split second before it was hidden behind the combined drapes of his hair and hood, spoke his answer.

She started to blink faster, fighting back near _tears_ of frustration. This was impossible, and worst of all, _unnecessary_. She knew better than anyone how long it took to get over a bout of awkwardness with a member of the guardians, as she still hadn't forgiven North for giving that aspiring dentist a firetruck instead of a set of dental equipment, and she also knew that the best way to get over such an ordeal was to face it head on.

Not really wanting to start up a week long screaming match with the young man, Tooth simply puffed up and trusted her instinct, leaning forward until he noticed her presence through the haze of his self-blame. Then she simply followed through, bracing herself against his shoulders as she pressed her lips against his, soft and sweet. It was chaste for the most part, but she couldn't resist a teasing nip to his bottom lip for his previous overzealous thing with the wind. He stilled at the first sign of contact and she broke away with a flushed smile. "Really, Jack. Thank you."

His eyes were wide with surprise and his mouth was starting to gape a little. Tooth felt doubt begin to creep in as she wondered whether this had really been the best idea to get _rid_ of the tense atmosphere. But then something seemed to _snap_ and with a sudden rush of chilly wind Jack pulled her forward and kissed her, unyielding and needy and she couldn't help a surprised gasp that he used to deepen it, their teeth clinking together in his want. He let out a sound of apology, humming against her lips but she simply dragged him closer by fistfuls of his hoodie, reminding him with an entirely affronted moan that _this was not the time to be sorry._

It dragged on for what seemed like forever, which, again, was a _very_ long time to an immortal guardian. When they finally broke apart due to nothing more than a need for air and a slight frostbite on her part, they were breathing heavily and he was staring at her with a strange look in his, unsurprisingly, dark eyes. "Wait, so you didn't, you still—"

Tooth struggled to bring her mind back to working order, hands letting loose of him in order to pat herself down. "What?"

Jack watched her struggle to smooth down her ruffled feathers with an intense look, as if he too was finding it trying to remember what he was talking about. His gaze trailed to her red and bruised mouth, when his own tongue darted out unconsciously to feel the impress of her teeth on his lips. "I—I mean." His eyes turned to hers, young and self-conscious and _needing_. "I though you didn't like me like that. Anymore. After." He ran a hand through his silver hair, which was just a touch longer now, "This."

It was her turn to gape, taking in the blue of his eyes with a certain incredulity. "You really thought? I mean." Her gaze turned disbelieving. "Jack, I've loved you for far longer than that!"

It was too late to take back her words, Tooth realized, but found she really didn't mind the accidental confession when the blue of his eyes could barely even be seen anymore, devoured by a dilating black that rendered the hypnotic color just a slim circle at the edge.

Jack leaned forward again and she hurried to meet him, foot forgotten because dammit, when the love of your immortal life finally understood that you didn't offer free peaks into their teeth's past to just _anyone_, you could get something as small as a broken foot fixed much, _much_ later.

After all, they weren't getting any younger.

.

.

.


End file.
